1. Field of the Invention
The present invention relates to a spindle motor and a hard disk drive including the same.
2. Description of the Related Art
An information recording reproducing apparatus, such as a hard disk driving apparatus, may be provided with a so-called fixed shaft spindle motor in which a shaft with strong vibration resistance is fixed to a case of a hard disk driving apparatus.
That is, a spindle motor mounted in the hard disk driving apparatus may adopt a structure in which a shaft is fixed, so as to prevent a state in which recorded information may be damaged and may not be written or read due to external vibrations.
Meanwhile, as the spindle motor used in the hard disk drive apparatus requires a high degree of reliability, there is a need to keep quantity of a lubricating fluid filling a hydrodynamic bearing assembly including a fixed shaft.
When the lubricating fluid is separated from a liquid-vapor interface formed between the lubricating fluid and air due to an external impact, vibrations, and the like, and leaked to the outside, the rotational characteristics of the spindle motor may be deteriorated and a rotating member and a fixed member forming a bearing clearance may be worn due to lack of the lubricating fluid.
Therefore, a need exists for the development of a structure capable of preventing the lubricating fluid from leaking to the outside.